Hi,
I'm using TMS320C6748 LCDK with xds100 v2 emulator to do some applications by using the book "Digital Signal Processing and Applications with the OMAP-L138 eXperimenter".
From the forum I know that "The textbook is compatible not only with the LogicPD OMAP-L138 eXperimenter but also with both the OMAP-L138 LCDK and the C6748 LCDK.".
I try to generate sine wave by using the code in Chapter 1, which is as follows
// L138_sine48_buf_intr.c //
#include "L138_aic3106_init.h"
#define LOOPLENGTH 48
#define BUFLENGTH 256
int16_t sine_table[LOOPLENGTH] = {0, 1305, 2588, 3827, 5000, 6088, 7071, 7934, 8660, 9239, 9659, 9914, 10000, 9914, 9659, 9239, 8660, 7934, 7071, 6088, 5000, 3827, 2588, 1305, 0, -1305, -2588, -3827, -5000, -6088, -7071, -7934, -8660, -9239, -9659, -9914, -10000, -9914, -9659, -9239, -8660, -7934, -7071, -6088, -5000, -3827, -2588, -1305};
int16_t sine_ptr = 0; // pointer into lookup table
int32_t buffer[BUFLENGTH];
int16_t buf_ptr = 0;
interrupt void interrupt4(void) // interrupt service routine {
int16_t sample;
sample = sine_table[sine_ptr]; // read sample from table
output_left_sample(sample); // output sample
sine_ptr = (sine_ptr+1)%LOOPLENGTH; // increment table index
buffer[buf_ptr] = (int32_t)(sample); // store sample in buffer
buf_ptr = (buf_ptr+1)%BUFLENGTH; // increment buffer index
return;
}
int main(void) {
L138_initialise_intr(FS_48000_HZ,ADC_GAIN_0DB,DAC_ATTEN_0DB);
while(1);
}
After I debugged the project, it says that
C674X_0: Output: Target Connected.
C674X_0: Output: Memory Map Cleared.
C674X_0: Output: Memory Map Setup Complete.
C674X_0: Output: PSC Enable Complete.
C674X_0: Output: PLL0 init done for Core:300MHz, EMIFA:25MHz C674X_0: Output: DDR initialization is in progress....
C674X_0: Output: PLL1 init done for DDR:150MHz C
674X_0: Output: Using DDR2 settings
C674X_0: Output: DDR2 init for 150 MHz is done
C674X_0: Output: DSP Wake Complete.
So I think that the configuration is correct.
When I run the c-code, the values in "sine_table"(16 bit signed integer) are correct, however, the values in the "buffer"(32 bit signed integer) which are for the output are wrong, i.e., the waveform is not sine.
In addition, I can't hear any sound from the output of the C6748 LCDK by earphoe.
Is it associated with the DIP switch or other settings, since I can generate and see the sine wave by C code only in simulation with CCS5, i.e., without using anything related to the C6748 LDCK?
Thanks.
Best regards,
PP
